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General Relativity
Stars orbiting black holes were observed to move significantly slower than expected. One explanation centers on dark matter.
Einstein called his idea "abominable," but the world of physics came around to embracing the views of Georges Lemaître.
Leading a scientific revolution is easy: you just have to succeed where the current theory fails while equaling its successes. Good luck!
If the evolution of the Universe is a movie, what happens when we rewind it all the way backward?
Time gets a little strange as you approach the speed of light.
What do we mean by a black hole's size? A photon sphere? The minimal stable orbit? The event horizon? The singularity? Which one is right?
Speeding through the Universe and leaving a wake of new stars, this runaway supermassive black hole is likely the first among thousands.
How scientists found out that we live in a cosmic aquarium.
Two very different ideas, wormholes and quantum entanglement, might be fundamentally related. What would "ER = EPR" mean for our Universe?
Not even Einstein immediately knew the power of the equations he gave us.
The zero-point energy of empty space is not zero. Even with all the physics we know, we have no idea how to calculate what it ought to be.
Unless you confront your theory with what's actually out there in the Universe, you're playing in the sandbox, not engaging in science.
Dark energy is one of the biggest mysteries in all the Universe. Is there some way to avoid "having to live with it?"
From the Big Bang to dark energy, knowledge of the cosmos has sped up in the past century — but big questions linger.
It is a story with nebulous beginnings and no discernible end.
19 years ago, the Bullet Cluster provided an empirical proof for dark matter. Even today, modified gravity still can't explain it.
In general relativity, white holes are just as mathematically plausible as black holes. Black holes are real; what about white holes?
Many people out there, including scientists, claim to have discovered a series of game-changing revolutions. Here's why we don't buy it.
There might be a hard limit to our knowledge of the Universe.
The information we have in the Universe is finite and limited, but our curiosity and wonder is forever insatiable. And always will be.
Yes, dark energy is real. Yes, distant galaxies recede faster and faster as time goes on. But the expansion rate isn't accelerating at all.
As time goes on, dark energy makes distant galaxies recede from us ever faster in our expanding Universe. But nothing truly disappears.
All the things that surround and compose us didn't always exist. But describing their origin depends on what 'nothing' means.
The science fiction dream of a traversable wormhole is no closer to reality, despite a quantum computer's suggestive simulation.
Perhaps wormholes will no longer be relegated to the realm of science fiction.
We'll never be able to extract any information about what's inside a black hole's event horizon. Here's why a singularity is inevitable.
We confidently state that the Universe is known to be 13.8 billion years old, with an uncertainty of just 1%. Here's how we know.
The strongest tests of curved space are only possible around the lowest-mass black holes of all. Their small event horizons are the key.
The Universe is 13.8 billion years old, going back to the hot Big Bang. But was that truly the beginning, and is that truly its age?